Gen 5 LT VVT Cam Phaser Lockout
Chevrolet Gen V mechanical lock out
These Chevrolet Gen V mechanical lock outs are used to prevent the VVT mechanism from retarding in high horsepower applications with high cylinder pressures. As cylinder pressures increase the amount of force needed to open the exhaust valves increases which can force the VVT mechanism to retard excessively. A phase limiter tool like Comp Cams 5456 for LT1, 5450 for LT4, or a spanner wrench are also needed.